The objective of this study is to investigate the effect of ball size on grinding kinetics in a pilot scale ball
mill. Six different ball media gradings were tested. Comparative tests were conducted in batch ball mill
having 1.2 m diameter and 0.6 m length at constant operating condition of mill such as media mass, mill
speed and input specific energy. Feed samples were ground batchwise and representative sample was
taken from inside the mill for each determined grinding period. Grinding process in ball mill was modeled
and the specific rate of breakage was calculated for the each test. The results indicated that the relationship
between different breakage rate and particle size has a maximum for each ball size distribution.
Consequently, a new equation to correlate maximum ball size and particle size at maximum breakage
occurs is proposed.